We propose to study the control mechanisms of colonic motility by doing: 1. A comparison of the kinds of nerves found in the cecum, proximal colon and distal colon in vitro, using the technique of electrical field stimulation. 2. Studies of the mechanical responses to pharmcaologic agnonists of muscle strips in vitro, comparing the circular muscle of cecum, proximal colon and distal colon. 3. Studies of the effects of neurogenic drugs on the electromyogram of the proximal colon and the distal colon in vitro. 4. Studies of the neuronal control of mass movements of the distal colon in vivo, using parasympathomimetic drugs and sympathomimetic drugs. 5. Studies of the hormonal control of mass movements of the colon in vivo, using gastrointestinal hormones. 6. Studies of the chemoreceptors and mechanoreceptors of the colonic mucosa in vivo.